Morphological responses of Capoeta gracilis and Alburnoides eichwaldii populations (Cyprinidae) fragmented due to Tarik Dam (Sefidrud River, Caspian Sea basin, Iran)

This study was conducted to evaluate the morphological responses of two different species including Capoeta gracilis and Alburnoides eichwaldii due to construction of the Tarik dam in the Sefidrud River using geometric morphometric technique. For this purpose, a total of 80 specimens of C. gracilis and 60 specimens of A. eichwaldii were collected from upstream and down-stream of dam. The left sides of specimens were photographed and14 and 18 landmark-points were digitized on 2D pictures of and C. gracilis and A. eichwaldii, respectively. The landmark data were submitted to GPA to remove non-shape data, analyzed by discriminate functional analysis and Ttest hotelling. The results showed no differences between the upstream and downstream populations of C. gracilis, but a significant difference found in A. eichwaldii in terms of body shape. The observed differences were related to head, snout, caudal peduncle regions and eye diameter that could be an adaptation to altered habitat and hydrological conditions of upstream and downstream due to damming. Different response of two studied species displayed that fishes can respond in different way to anthropogenic modifications of riverine ecosystem.